Using a hockey reference, Gondek said: ‘We need to play the full 60 minutes, and right now we’re in the last five minutes of Game 7’
The five “hot spots” in the ruptured water feeder main have been fixed, city officials announced Tuesday, as Calgary heads into the critical stage of filling the pipe with treated water and ensuring it is safe to drink.
“To be clear, the repair work is done,” Mayor Jyoti Gondek said in a news conference — however, Calgary is still not in the clear.
While the city overcomes a major hurdle by mending the damage to its main pipe that carries drinking water to the rest of the city, the challenge it now faces is to bring the feeder main back into use through four stages: filling, flushing, testing and stabilizing.
Using a hockey reference, Gondek said: “We need to play the full 60 minutes, and right now we’re in the last five minutes of Game 7.”
The first stage involves filling a 4.5-kilometre stretch of the pipe with 14 million litres of water from the Bearspaw treatment plant. The city will then monitor for the potential for any further breaks.
“We’re managing this risk by filling the pipe carefully and using acoustic monitors to listen for pings that can indicate further wire breaks,” said Francois Bouchard, director of the city’s capital priorities and investment, adding the city will also use sensors to detect unusual activity.
The process, which will take two days, is set to begin Wednesday night.
Parts of Edworthy Park to be closed
Once the pipe is filled, the city will push the water out of the pipe to flush out any impurities resulting from the major repairs. The liquid, which will be dechlorinated, will exit through valves and fire hydrants with hoses that will run through part of Edworthy Park and into the river.
As a result, a section of the north side of Edworthy Park and the North Edworthy parking lot will be closed, and adjacent pathways will be temporarily detoured, Bouchard said.
“While we do the flushing, people will be able to see this water flowing and it might look as if we’re wasting water,” he said. “Please know that this process is a critical part of making sure our water is safe to drink.”
That stage will take one day if the city doesn’t experience any new breaks.
‘This is delicate work’
The water will then be tested with the help of specialists at Alberta Health Services — a process that will last about two days.
If the results meet the city’s safety requirements, the city will loosen the valves pouring water into the feeder main. This would increase the pressure on the pipe, leaving it vulnerable to other breaks.
Stabilizing the structure would take between three and five days.
The entire process should take less than two weeks, but the city also emphasized a major caveat: “This is delicate work. Each one of these steps carries the risk that we could have some setbacks along the way,” Bouchard said.
As a result, the city stopped short of offering a timeline for the final stages of the pipe’s restoration, although Gondek suggested that the work could be completed before Stampede begins on July 5.
Mayor cautions against rising water use
Meanwhile, Gondek applauded the efforts of Calgarians to save water, while highlighting that usage rose to 476 million litres on Monday — slightly lower than the city’s threshold of 480 million litres a day.
“If this was a one-day blip, I might not be so concerned,” Gondek said.
“But this is again the trend of creeping upwards in our water usage, and it’s not a trend that any of us want to see.”
The city, which has also begun providing residents access to river water — which is not safe for drinking — at six filling stations, has added another location to its list: Fish Creek Park. More than one million litres of water have been collected from the six sites since Sunday, including 31,000 litres taken by residents.
The city also announced it would resume street sweeping if it didn’t encounter any further issues in the final stages of restoring the pipe, without providing a timeline for deactivating outdoor and indoor water restrictions.
The city has received 2,741 calls reporting water misuse since June 6, which have resulted in 835 verbal warnings and 17 violation tickets. Concerning fire bans, the city received 224 calls, which led to 24 written warnings, 85 verbal warnings and five violation tickets.